In-band signaling for routing

ABSTRACT

Telephone call routing in networks is provided by forwarding routing data other than origination identification and destination identification in-band with calls, and using the in-band data at call destinations to do further routing. In some embodiments negotiation is accomplished between routers at different points in the network based on the in-band routing data. Practice of the invention extends to intelligent telephony networks and as well to simulated telephone calls between computers in wide area data networks, such as the Internet and Intranets.

CROSS-REFERENCE TO RELATED DOCUMENTS

The present application is a Continuation-In-Part (CIP) of applicationSer. No. 08/879,619, filed Jun. 20, 1997, which is a CIP of Ser. No.08/802,660 filed Feb. 19, 1997, which is a CIP of Ser. No. 08/797,407filed Feb. 10, 1997, all of which are incorporated herein in theirentirety by reference reissue of U.S. Pat. No. 6,104,802, filed on Nov.18, 1997.

FIELD OF THE INVENTION

The present invention is in the field of computer telephony and hasparticular application to intelligent network call routing.

BACKGROUND OF THE INVENTION

Telephone call processing and switching systems are, at the time of thepresent patent application, relatively sophisticated, computerizedsystems, and development and introduction of new systems continues. Muchinformation on the nature of such hardware and software is available ina number of publications accessible to the present inventor and to thosewith skill in the art in general. For this reason, much minute detail ofknown systems is not reproduced here, as to do so would obscure thefacts of the invention.

One document which provides considerable information on intelligentnetworks is “ITU-T Recommendation Q.1219, Intelligent Network User'sGuide for Capability Set 1”, dated Apr., 1994.

At the time of filing the present patent application there continues tobe remarkable growth in telephone-based information systems, which areintelligent networks. Recently emerging examples are telemarketingoperations and technical support operations, among many others, whichhave grown apace with development and marketing of, for example,sophisticated computer equipment. More traditional are systems forserving customers of such as large insurance organizations. In somecases organizations develop and maintain their own telephony operationswith purchased or leased equipment, and in many other cases, companiesare outsourcing such operations to firms that specialize in suchservices.

In telephony art, much commercial development is in the area of what areknown as call center services and systems, wherein an organizationmaintains one or more call centers manned by agents of the organizationto provide services to clients of the organization. The call centers aretypically based on a telephony switch such as a PBX, having incomingtrunks and station-side ports connected to agent stations having a leasta telephone. Incoming calls are routed to agents based in any of manypossible routing criteria. In relatively more state-of-the-art callcenters the switches are computer enhanced by being connected toprocessors running applications for providing additional services notprovided by the switch alone. In the art the processes of suchenhancement are known as computer telephony integration (CTI). It is tosuch systems that embodiments of the present invention are principally(but not exclusively) directed. Embodiments will in general be describedrelative to call centers.

In an intelligent telephony network such as described herein, incomingcalls placed from anywhere in the Public Switch Telephone Network (PSTN)are typically routed by computerized systems known in the art as ServiceControl Points (SCPs.

Additional processors and software may be provided associated with anSCP for further computer enhancement. For example, when a call arrivesat a control point, information about the caller may be collected andprocessed to help determine the final destination of the call. Thenaccording to programmed routing rules, the call may be switched to acall center and then on to an available agent. In many intelligentnetworks known to the inventor, digital information pertaining to thecaller may be sent ahead to a call center by means of a data linkseparate from the call carrier, the data link implemented between theSCP and the call center, typically through a CTI processor connected tothe telephony switch at the call center. Routing in an intelligentnetwork may be accomplished on several levels according to manydifferent protocols.

A problem with routing within a conventional network is that the finaldestination for a call is often determined before the call leaves theSCP and further routing is largely automated at decentralized telephonyswitches within the network. This increases the possibility of errors inrouting. Calls may be incorrectly routed in the first instance, and,since call transfer is a process that takes a certain length of time,there may be changes while a call is routed, so when the call arrives atthe destination, the situation may have changed to the point that thecal will have too be re-routed. Further, the information at an SCP foruse in determining routing of calls is typically information updatedperiodically, and not real-time data.

Another recent development in telephony art is what is known as InternetProtocol Network Telephony (IPNT), wherein conventional telephone callsare simulated between computers over the data network known as theInternet, using microphones and speakers operating with the computersand a graphical user interface operable on each connected computer.Several commercial vendors offer software for simulating such telephony,and similar systems may operate with data networks other than theInternet, such as through company Intranets. At the time of the presentpatent application such data networks are considered largely “dumb”networks rather than intelligent networks, although some routing isdone. Calls are routed in the Internet, for example, by IP addresses,and IP switches and hubs are capable of altering the destination of datapackets by controlling IP addresses. In embodiments of the inventionthat follow, although intelligent telephony networks are used in themain for examples of practicing the invention, the features of theinvention are meant to apply as well to IPNT.

What is clearly needed is a better system and method to do call routingwhereby determination for routing calls can be shared with decentralizedrouters in the field without using a separate digital network fortransmitting data. In such a system determination of final routing canbe made as close as possible to final destination, and information usedfor routing can be maintained in much closer to real time.

SUMMARY OF THE INVENTION

In a preferred embodiment of the present invention a method for routinga telephone call in a network is provided, comprising steps of (a)attaining, at a first network destination point, routing data associatedwith the call other than origination identification or first destinationidentification; (b) forwarding the routing data in-band with the call toa second network point; (c) accessing the routing data at the secondnetwork point; and; (d) using the routing data to select a third networkdestination for the call.

In some embodiments of the method the network is an intelligenttelephony network routing telephone calls, and the first destinationpoint is a service control point (SCP). In these embodiments the routingdata other than origination identification or first destinationidentification may be data elicited from a caller. In some embodimentsas well, the data is overwritten by a first router at the first networkpoint into one or more data fields conventionally dedicated toinformation other than the routing data. In such embodiments, in steps(c) and (d) the accessing and using is by a second router at the secondnetwork point, and the first router and the second router may negotiaterouting path.

In other embodiments the network is a wide area data network., and thetelephone calls are simulated calls between two or more computerstations connected to the wide area data network. In the case of callsimulation in a wide area network, at the first network destinationpoint a first router writes routing data into one or more data fields ina data packet associated with the call, and forwards the data packet toa second destination point for further routing by a second router usingthe routing data.

In another aspect of the invention a routing system for telephone callsin a network comprising a first router associated with a first networkdestination point; and a second router associated with a second networkdestination point. For a call received at the first network destinationpoint, the first router writes routing data other than call originationidentification or first destination identification into one or more datafields conventionally dedicated to other than the routing data, and thesecond router at the second network destination point uses the routingdata from the one or more data fields to further route the call. Insystems of the invention the network may be an intelligent telephonynetwork with the first destination point a service control point (SCP)and the second network destination point a computer-telephony integrated(CTI) telephony switch at a call center. In such an embodiment the firstrouter and the second router negotiate based on the data written by thefirst router into the one or more data fields.

In an alternative aspect of the invention the network may be a wide areadata network., and the telephone calls are calls between two or morecomputer stations connected to the wide area data network rather thanbetween telephones, the computers providing telephone functions. Thewide area data network may the Internet, wherein the calls are InternetProtocol Network Telephony calls, or may be an Intranet.

A distinct advantage of the present invention is that no separate datanetwork is necessary in an intelligent telephony network for the purposeof delivering routing data to a second (or further) destination point.Such data arrives with the call or with a data packet associated withthe call. Negotiation is still possible, and there is little difficultyin associating the data with an arriving call.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 is a simplified overview of an intelligent network as known tothe inventor before the present invention, but not in the public domain.

FIG. 2 is a simplified overview of an intelligent network using anin-band signaling technique according to an embodiment of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a simplified overview of an intelligent network known to thepresent inventor wherein incoming calls are represented by a vector 107arriving at a Service Control Point (SCP) 101 in Network cloud 100.Network cloud 100 may be a Publicly Switched Telephony Network (PSTN), aprivate network, or any other wide area network (WAN) of telephones andconnected equipment.

An adjunct processor 104 in this instance is associated with the SCP,and is provided for the purpose of computer enhancement. Adjunctprocessor 104 may contain or be connected to other applications known inthe art such as a call distributor (CD) and an intelligent peripheral(IP) 102. IP 102 typically provides enhanced capability related toobtaining caller information such as by interactive voice response (IVR)techniques and so on. There may also be additional capabilitiesattributed to adjunct processor 104 such as an instance of a routingapplication or an instance of a stat-server, which is a server thatstores updated statistical information and provides such information forrouting purposes.

When a call 107 arrives at SCP 101, information is typically elicitedfrom the caller using the capabilities of IP 102. This information andinformation stored in the statserver, comprising such as agentavailability and load statistics, is used to determine routing for call107. In prior art intelligent networks, routing is typicallypredetermined before call 107 leaves SCP 101.

Two call centers 121 and 122 are shown in FIG. 1. It will be apparent tothose with skill in the art that there may be many more than two suchcall centers, but two is considered adequate to describe the prior artin the present case. When routing is determined at SCP 101, the incomingcall may be switched to either of centers 121 or 122. In the instanceshown in FIG. 1, call centers 121 and 122 are computer-enhanced. Acomputer telephony integration (CTI) processor 223 is connected toswitch 123 at center 121 and a CTI processor 224 is connected to switch124 at center 122. A bi-directional data link 110 connects processor 223to adjunct processor 104 and a bi-directional data link 111 connectsprocessor 224 to adjunct processor 104.

When routing is determined at SCP 101 to one of call centers 121 and122, information solicited from a caller may be forwarded via theappropriate data link, 110 or 111, to the call center, where the datamay be used for purposes such as a key to retrieve information from adata base to aid an agent in serving the caller.

Call center 121 comprises two agent stations, agent station 131 andagent station 132. Similarly call center 122 comprises two agentstations, agent station 133 and agent station 134. Agent stations 131through 134 are equipped with telephones 136, 138, 140, and 142respectively. In some embodiments, agent stations such as describedabove may have computer platforms connected to video display units(PCNVDUs), not shown in FIG. 1. It will be apparent to one with skill inthe art that there may be many more agent stations and telephones. Call107 is forwarded over lines 105 or 106 to the appropriate call center,depending upon routing determined at the SCP. Upon reaching the callcenter, call 107 is then distributed to an available agent at one oftelephones 136, 138, 140, or 142, via programmed routing executed fromeither processor 223 or processor 224.

FIG. 2 is a simplified overview of a system according to an embodimentof the present invention wherein a method of in-band signaling isuniquely applied to provide intelligent routing with routing decisionsmade closer to final call destination, and affording some level ofnegotiated routing. The system represented by FIG. 2 contains many ofthe components described above for the system of FIG. 1. Repetition ofelement introduction is not repeated for FIG. 2.

A typical means of routing calls is by use of the calling party's numberand/or the destination number. It is known in the art to transfer suchinformation when forwarding a call, by means of what is known asAutomatic Number Information (ANI number) and Destination NumberIdentification System (DNIS). Depending on the nature of the equipmentused, the network itself, and software, the actual mechanisms forproviding these numbers may vary. For example, with older analogtelephone equipment and lines, a call is sent to a receiving point bycoded voltage difference between a pair of wires. In this case, a winkand blink system is used to establish contact, then ANI and/or DNISnumbers may be provided coded as a header to the call before analogaudio signals are established.

As another example, using later digital equipment and controllingsoftware, a data packet having data fields dedicated to ANI and/or DNISmay precede a call, making this information available to a receivingstation. Data fields are more recognizable in the digital example, butthe preceding coded information sent with an analog call may also beconsidered to be sent in a dedicated field. The nomenclature of adedicated data field is used herein to include analog calls as well asdigital calls.

In either case, analog or digital, the ANI number and DNIS number may beconsidered “in-band” information. That is, the information accompanies(or precedes) the telephone call, and is transmitted on the samecommunication link as the telephone call. In the case of IPNT calls,over, for example, the Internet, information is sent by data packets,including fields for various purposes, such as an IP address, inaddition to digital audio data. This data may be considered as in-banddata as well, and the in-band fields are dedicated fields for aparticular purpose. Also, in each case, the protocols and methods bywhich the in-band information is transmitted are well-known in the art.

In embodiments of the invention described below, available in-band datafields are adapted to carry routing information associated with atelephone call for purposes of routing calls and negotiating routingwith routers located at various levels in a network.

Referring now to FIG. 2, a router application 201 and an instance of aCTI application 202 known to the inventors as T-server execute atadjunct processor 104 in the network cloud. Router application 201 usesinformation typically elicited from callers or retrieved from a databaseassociated with a call, and uses that information along with possiblyadditional information available to generate routing for calls accordingto routing protocol in the network. It will be apparent to one withskill in the art that applications such as router application 201 andT-server application 202 may reside in a single processor, or more thanone processor that is associated with SCP 101 without departing from thespirit and scope of the present invention. Separation of theseapplications and processors is done here for illustrative purposes only.

In a preferred embodiment of the present invention CTI processor 223executes instances of router application 201 as well as T-serverapplication 202. Similarly, CTI processor 224 executes an instance ofrouter application 201 and T-server application 202. Using thisparticular configuration of a central router and decentralized routers,in-band signaling is practiced between the routers in variousembodiments of the invention to provide intelligent interaction betweenthe routers. Existing data fields are used to forward routinginformation other than ANI and DNIS numbers by manipulating existingin-band signal fields. Such dedicated fields are completely or partiallyoverwritten with routing data, and this information is then transmittedin-band over telephony lines 105 and 106 as described above.

As just one of many possible examples, if it is determined that call 107is to go to an agent that speaks Spanish and is trained to providetechnical assistance with a particular product, then router application201 at the network level would, in an embodiment of the invention,overwrite a portion of an in-band signal field with this information. Itwill be apparent to those with skill in the art that this data set isbut one of very many that might be extant in different situations fordifferent organizations.

There are a number of existing fields in telephony that may be utilized.For example, in the AT&T™ network there is a Customer Data Field (CDPD)provided by the carrier at the SCP and then delivered and used by aG3-type switch. This field may be used to provide in the telephone calla key or actual data, or a combination of the two. In other networks,such as MCI for example, there are similar fields whose conventional usemay be coopted for routing purposes. The Destination Number InformationService (DNIS) field may be similarly over written with routing data.

Router application 201 has the ability to configure and execute routingdata overwrites to different fields generic to different switches and ornetworks such as AT&T, MCI, Rockwell, Lucent or Northern Telecom, and soon. The manipulated in-band signal then carries the routing data over,for example, conventional telephony line 105 to telephony switch 123where an instance of router application 201 residing in CTI processor223 can read the information and use it to route call 107 to an agentconnected to a station-side port at the call center. By utilizingin-band signaling for routing, in some instances network connections 110and 111 can be eliminated. All routing in such embodiments can beprovided in the form of in-band signaling from the network to routers atlower levels.

There are some possible problems which have occurred to the inventor.For example, it is inevitable that there may be some mistakes onoccasion in initial routing of calls with in-band data. A problem mayarise because in-band signaling for routing purposes may seem at firstglance to be single-directional, from the higher-level router to thelower. In various embodiments of the invention, however, a level ofnegotiation may yet be provided between the higher-level router and thelower. For example, in one embodiment, software may be providedassociated with both sending and receiving routers such that if thereceiving router is not prepared to handle a particular call by thenature of the in-band routing data, the receiving router may cause thereceiving equipment to respond to the call with a busy signal. The busysignal may be interpreted by the sending router as a return signal thatthe call is refused, and should be routed to an alternative destination.Similarly a number-of-rings (time) protocol could accomplish similarnegotiation.

In some embodiments using ISDN lines in place of conventional telephonylines, additional communication between instances of router application201 in bi-directional fashion is possible, as a return signal may besent over one of the ISDN channels.

It will be apparent to those with skill in the art that an intelligentnetwork such as the one described with reference to FIG. 2 whereinin-band signaling is manipulated to provide routing instruction may beimplemented in a wide variety of architectures without departing fromthe spirit and scope of the present invention. For example, such anintelligent network scheme may comprise many call-centers andCTI-enhanced telephony switches, may or may not employ a separatenetwork for data communication between routing points in the network,and may use different types of telephony lines or trunks.

In the matter of IPNT, it should be apparent that an Internet call, forexample, may be directed to a first destination, which may be adapted tocommunicate with and elicit information from a caller, and also in someinstances to retrieve additional information from stored resources.Routing intelligence at the first destination may then encode all orpart of such information in one or more data fields of data packets anddirect the data packets to a second destination, wherein the encodedin-band data may be used to further route the call. Negotiation may beaccomplished between the first and the second routers resulting infurther routing determination, and there is no real limit to the numberof iterations that may be performed. Thusly, as in an intelligentnetwork as described above, routing may be forced to levels closer andcloser to final destinations, where decisions may be made on informationmore apt to be closer to real-time.

It will also be apparent to those with skill in the art that the methodof the present invention wherein in-band signaling is used may beadapted to differing types of telephony switches without departing fromthe spirit and scope of the present invention. It is well known that thefunctions of telephony switches offered by different manufacturers mayvary. However, the in-band signaling properties available with theseswitches are similar so that a router could be adapted to overwrite thedata fields therein. A routing application may be programmed to enablethe overwrite of in-band signal fields of several different switchesthat may be employed on the same network. There are many suchpossibilities many of which have already been described. The spirit andscope of the present invention is limited only by the claims thatfollow.

What is claimed is:
 1. A method for routing a telephone call in anetwork comprising steps of: (a) attaining, at a service control point,routing data associated with the call other than originationidentification or first destination identification; (b) writing therouting data in-band, in a data field conventionally dedicated toinformation other than routing data, with the call to forward to asecond network point serviced by a computer-telephony integration (CTI)system; (c) accessing the routing data at the second network point bythe CTI system; and; (d) using the routing data to select a thirdnetwork destination for the call.
 2. The method of claim 1 wherein, instep (a) the routing data other than origination identification or firstdestination identification is data elicited from a caller.
 3. The methodof claim 1 wherein, in steps (c) and (d) the accessing and using is by asecond router at the second network point, and wherein the first routerand the second router negotiate routing path.
 4. The method of claim 1wherein the network is a wide area data network, and the telephone callsare simulated calls is between two or more computer stations connectedto the wide area data network.
 5. The method of claim 4 wherein at thefirst network destination point a first router writes routing data intoone or more data fields in a data packet associated with the call, andforwards the data packet to a second destination point for furtherrouting by a second router using the routing data.
 6. A routing systemfor telephone calls in a network comprising: a first router associatedwith a service control point; and a second router associated with asecond network destination point serviced by a computer-telephonyintergration integration (CTI) system; wherein, for a call received atthe service control point, the first router writes routing data otherthan call origination identification or first destination identificationinto one or more data fields in a data packet associated with the callconventionally dedicated to other than the routing data, and the secondrouter at the second network destination point uses the routing datafrom the one or more data fields to further route the call, and whereinthe first router and the second router negotiate based on the datawritten by the first router into the one or more data fields.
 7. Thesystem of claim 6 wherein the first router and the second routernegotiate based on the data written by the first router into the one ormore data fields.
 8. The system of claim 6 A routing system fortelephone calls in a network comprising: a first router associated witha service control point; and a second router associated with a secondnetwork destination point serviced by a computer-telephony integration(CTI) system; wherein, for a call received at the service control point,the first router writes routing data other than call originationidentification or first destination identification into one or more datafields in a data packet associated with the call conventionallydedicated to other than the routing data, and the second router at thesecond network destination point uses the routing data from the one ormore data fields to further route the call, wherein the first router andthe second router negotiate based on the data written by the firstrouter into the one or more data fields, and wherein the network is awide area data network, and the telephone calls are calls between two ormore computer stations connected to the wide area data network ratherthan between telephones, the computers providing telephone functions. 9.The system of claim 8 wherein the wide area data network is theInternet, and wherein the calls are Internet Protocol Network Telephonycalls.